A five-rupee coin is put on a thick smooth card and place it on a glass tumbler. Now flick the card horizontally striking it hard with your finger at one of its corners. Explain what you observe.

• Take a thick sheet of cardboard and make a small hole or narrow slit in its middle. • Allow sunlight to fall on the narrow slit. This gives a narrow beam of white light. • Now, take a glass prism and allow the light from the slit to fall on one of its faces as shown in Fig. • Turn the prism slowly until the light that comes out of it appears on a nearby screen. What do you observe? You will find a beautiful band of colours.